Cats are among the most popular household pets in the world - they've spread across the planet and have even been launched into orbit. But for a long time, scientists have been unsure about precisely how cats became our stalwart companions. In today's DNews report, Amy Shira Teitel discusses a new study that may have the answers.

Geneticists using scraps of mitochondrial DNA have determined that cats very likely traveled the world in the ships of Vikings, who used the feline hunters for pest control. In the Mediterranean, cats were useful in early agricultural communities for much the same reason. Amy has more details on the study, which traced the lineage of household cats back more than 15,000 years.